The present invention relates to a cathode ray tube socket designed to be used in conjunction with a cathode ray tube having one or more high voltage terminals as well as a plurality of low voltage terminals, and more particularly to such a socket providing spark gap protection for the high voltage terminals, preferably together with separate spark gap protection for the low voltage terminals.
U.S. Pat. No. 3,865,452 describes a cathode ray tube socket having dual spark gap protection, i.e., having two separate and independent grounding capabilities such that the high voltage terminal has a high voltage grounding member, the low voltage terminals having a common low voltage grounding member, and a spark which has jumped from the high voltage terminal (normally operated at 25,000 volts D.C. or greater) to the high voltage grounding member cannot jump back to any of the low voltage terminals (normally operated in the range of a few thousand volts) and thus damage the tube. The socket therein described is especially adapted for use with cathode ray tubes having a plurality of low voltage pins and a single high voltage pin.
A recent development in the cathode ray tube field is a tube having not only a plurality of low voltage pins, but also a plurality of high voltage pins (i.e., pins normally operated at 10,000 volts or higher), generally two of the high voltage pins. A tube socket of the design specifically disclosed in U.S. Pat. No. 3,865,452 does not easily lend itself to adaptation for use with the new tubes for a number of reasons. As the length of the air gap required to provide spark gap protection is a positive function of the operating voltage of the terminal to be protected, two relatively large air gaps must be maintained in a single tube socket while maintaining the socket as small and compact as possible. Furthermore, means must be provided for isolating and expelling from the interior of the tube socket any ozone produced by sparking of one of the high voltage terminals before that ozone has an opportunity to ionize the air in the air gap associated with the other high voltage terminal and thus lead to premature firing of that other high voltage terminal. Finally, means must be provided to isolate and contain high voltage sparking as the use of a plurality of high voltage terminals introduces the possibility of sparking of one high voltage terminal affecting the other high voltage terminals, as well as increasing the possible danger to equipment in the area from the sparking of any one of the high voltage terminals.
As the new tube types are more sensitive than the old tubes, the new tubes, whether they employ one or a plurality of high voltage pins, are more likely to produce noise or static in the presence of a corona effect. Such a corona effect results from the use of a high voltage terminal having points or sharp edges and causes ionization of the air about the sharp edge or point, thus making the air more conductive and leading to a lower voltage breakdown point for all pins in the area of the ionized air. Where the new tubes employ a plurality of high voltage pins, the corona effect produced by one high voltage terminal is capable of affecting the other high voltage terminals in the area, and thus the avoidance of a corona effect is of even greater importance when the tube employs a plurality of high voltage pins.
It will be recognized by those skilled in the art that the isolation and expelling of ozone, the isolation and containment of high voltage sparking, and the minimization of corona effect are all desirable features of a tube socket, albeit in differing degrees, regardless of whether the socket affords dual spark gap protection, single spark gap protection, or even no spark gap protection.
In my pending application Ser. No. 823,616, filed Aug. 9, 1977 and entitled "Tube Socket With Dual Spark Gap Protection", assigned to the assignee of this application, I disclose a tube socket capable of accomplishing the features set forth above and specially designed for use with a cathode ray tube which not only carries two separate high voltage pins, but which houses those pins within silo structures for protective purposes. That socket, while it accomplished its desired results, was comparatively bulky, the shape of its molded insulating parts was quite complex, it was difficult to assemble, and hence it was costly to manufacture.
For example, the fact that the structure defining the chambers for the high voltage spark gaps was a part separate from the remainder of the socket structure, and which was in itself complex of shape and difficult and expensive to mold, contributed greatly to the overall cost and expense of the socket. In addition, in general the assembly of the terminals and spark gap elements with the insulating support portions of the socket presented production problems, particularly insofar as the high voltage terminals and the spark gaps associated therewith were concerned.
It is an object of the present invention to provide a tube socket for use with a cathode ray tube of the type having one or more high voltage pins as well as a plurality of low voltage pins, which socket is amenable to low cost manufacture without sacrifice of electrical properties.
Another object is to provide a tube socket which has a novel means for isolation and venting of ozone produced by sparking of a high voltage pin.
A further object is to provide a tube socket which minimizes the production of corona effect from a high voltage terminal.
Yet another object is to provide such a tube socket which can readily have incorporated thereinto means for spark gap protection for the low voltage terminals.
Still a further object is to provide such a tube socket for use with a tube having a plurality of high voltage pins, the tube socket minimizing the production of corona effect from any of the high voltage terminals.
It is also an object to provide such a tube socket of simplified construction which effectively isolates and contains sparking from any of the high voltage terminals, thereby to protect the other high voltage terminals as well as other equipment in the vicinity.
It is another object to provide a tube socket which is easily and inexpensively manufactured, yet sturdy and compact in design and functionally effective.
Yet another object is to provide any or all of the above features in a tube socket affording dual spark gap protection.